Fluid simulation is choppy with animated obstacle descending on Z axis [video included]
That's not an error; that's simply Blender telling you that your fluid it too low res. Generally, I would say, "up the Final Resolution: for a smoother result," but that won't help that much in your case (150 should be plenty for most anything).

However, in this case, the issue is that your Domain is HUGE!!! The Domain should be exactly that; a cube that encompasses anywhere your fluid might travel and NOTHING ELSE! So if you scale your domain cube from Img 1 (where it currently is) to Img 2 (what I am suggesting), your resolution (being relative to the size of the Domain) will "increase."

Img 1; how you have it:



Img 2; what I'm recommending:



Notice how it only encompasses where the water will be. Lastly, consider the following image, which shows how your fluid will bake after the modification (so much more concentration!).

I only let it bake the first frame, because baking will now take longer:



Here is a .blend file with the modifications: